Roast the pinenuts in a pot (the one you use later for the pasta is fine).
Add roasted pinenuts to the salt and garlic to grind them all together.
Add the basil, cheese, and oil in small quantities and pound them as you go.
Main:
Dice onion and fry it up in olive oil with the pancetta. It's a good idea to put the pasta water
on now too.
Once they have softened, add in the freshly chopped mushrooms and cover.
Boil the pasta water and cook the pasta as per the required time, remembering to salt the water
once the pasta is in.
After 10-15 minutes, add in 2-4 tbsp of fresh pesto to the mushroom mix, and turn off the heat
as you fold it in.
Cooking it for too long reduces the flavour and the punch of the garlic/basil.